Purification of the Eucaryotic Heat-Shock Proteins Hsp70 and gp96

Heat-shock proteins (HSPs), highly conserved across species, are generally considered as intracellular proteins that have protective functions in situations of cellular stress. A wide variety of stressful stimuli like heat shock, ultraviolet radiation, and viral or bacterial infections induce a substantial increase in intracellular HSP synthesis (1 ). The main functions ascribed to HSPs (not only restricted to situations of cellular stress) are to act as chaperones of nascent or aberrantly folded proteins. From the immunological point of view, HSPs have obtained significant interest because it could be shown that HSPs like Hsp70 and gp96 purified from tumor and virus-infected cells are capable of eliciting a protective CTL-mediated immunity (2 ,3 ). This immunogenicity is based on antigenic peptides that are associated with Hsp70 and gp96 molecules, and peptide-deprived HSP complexes lose their immunization capacity (4 ).